Roller thrust bearings are known and used in a variety of applications for supporting axial loads. Such applications may include a torque converter, a transmission plate, an automatic transmission clutch carrier, a planet gear carrier, a ring gear carrier, and other automatic transmission components that require at least one thrust bearing.
Typical thrust bushings or washers are separate components assembled between rotating components and formed from a variety of materials from steel to resin-soaked paper. For a resin-soaked paper (or other fiber matrix substrate), the paper accommodates irregularities in the mating surfaces in rotating components, but can be susceptible to wear. Thrust bushings must provide a very low coefficient of friction while having very high durability. In applications with an oil bath with pressure and velocity (PV), typical thrust bushing materials such as resin-soaked paper experience problems due to heat and wear. Ideally, a thrust bushing in a torque converter should last the entire useful life of a vehicle. In torque converter applications, the thrust bushing must be able to with stand PV values up to 5.5 (N/mm2)*(m/sec). Manufacturing costs are also a concern for producing thrust bushings.